Waveguide switches are key hardware used for redundancy switching and signal routing, thanks to their outstanding reliability and very high power handling capacity.
U.S. Pat. No. 2,814,782 describes a waveguide switch comprising first and second rectangular waveguides joined to form a first double mitered ninety degree E-plane bend, the mean distance between miters being approximately equal to one quarter of a guide wavelength, a third rectangular waveguide collinear with said second waveguide and extending in the opposite direction from said bend, means for rotating the outer section of said bend about its midpoint whereby when rotated through ninety degrees, a second bend comprising said first and third waveguides and said section is formed, and dielectric filled slots one quarter wavelength deep formed in opposite edges of said outer section.
U.S. Pat. No. 4,806,887 describes a waveguide R-switch having transformers in one or more of its three waveguide paths. The presence of the transformers allows the R-switch to be constructed of a smaller size than previous R-switches with curved outer paths.
U.S. Pat. No. 6,667,671 B1 describes a waveguide switch having a stator and an electrically conducting movable element, the stator having waveguide paths between waveguide terminal pairs, each path being switchable to conducting or nonconducting with the help of the movable element for high-frequency waves. The movable element is designed as a septum in a gap in the stator and extends in the waveguide path, which is switched to nonconducting, in parallel to its E plane. This divides the waveguide path into two partial waveguides, which run in parallel with one another and, in comparison with the switched-to-conducting state of the waveguide path, have smaller cut-off wavelengths.
U.S. Pat. No. 4,242,652 describes a waveguide switch having four RF ports in coplanar relationship and incorporating four waveguide transmission lines in a single rotating mechanism on two levels, the rotating mechanism being driven by an electromagnetic stepper motor or the like.
U.S. Pat. No. 4,908,589 describes a dielectrically loaded waveguide switch including first and second dielectrically loaded waveguides selectively connected by a switch. The switch includes a third dielectrically loaded waveguide mounted for communication with said first and second waveguides upon switch actuation.
FIG. 13 shows an example of a conventional switch 2. The switch 2 enables selective connection between pairs of four transmission lines 11-14 which allow for propagation of electromagnetic waves. The switch 2 comprises a rotatable switching portion 3 for a pairwise connection of the four transmission lines 11-14. In the first position of the switching portion 3 which is illustrated in FIG. 13, the first transmission line 11 is connected with the fourth transmission line 14 but disconnected from the second transmission line 12 and the third transmission line 13 which are connected with each other. Upon rotating the switching portion 3 by 90 degrees in a clockwise direction, the first transmission line 11 is connected to the second transmission line 12 and the third transmission line 13 is connected to the fourth transmission line 14. The switching portion portion 3 can be rotated further in steps of 90 degrees to connect any one of the four transmission lines 11-14 with one of its adjacent transmission lines 11-14 and to connect the remaining two transmission lines at the same time.
Switches 2 are frequently applied in multiplexer configurations for changing the routing of the input signal, as is illustrated in FIG. 14A. The exemplary multiplexer 4 comprises three signal ports 110, wherein the signal port 110 on the left hand side is used as an input port and the two signal ports 110 on the right hand side are used as output ports. The multiplexer 4 further comprises four signal filters 120a-120d of which signal filters 120a and 120c pass the frequency range ch1, the signal filter 120b passes the frequency range ch2 and the signal filter 120d passes the frequency range ch2a. Additionally, three switches 2a-2c are provided in the multiplexer for changing the signal routing along the transmission lines 150 connecting the components of the multiplexer 4. Furthermore, the multiplexer 4 may comprise branching junctions 130 for interconnecting three transmission lines 150.
By switching all of the switches 2a-2c from a first state (not shown) of the multiplexer 4 to a second state of the multiplexer 4 (as shown in FIG. 14A), the combined frequency bandwidth of the output signal can be changed from ch1+ch2 (first state) to ch1+ch2a. This situation is schematically illustrated in FIG. 14B where the top scheme shows the frequency range of the output signal when the multiplexer 4 of FIG. 14A is in the first state and the bottom scheme shows the frequency range of the output signal when the multiplexer 4 of FIG. 14A is in the second state.
FIG. 15 illustrates another exemplary multiplexer configuration with four input ports 110, a first output port 111 and a second output port 112. The purpose of this multiplexer 4 is to provide signals at the first and second output ports 111, 112 which both contain the frequency range ch1 in any case and might additionally contain the frequency ranges ch2 and/or ch3. For this purpose, two switches 2a, 2b and six signal filters 120 are provided in the multiplexer 4. The switch 2a can allocate the frequency range ch2 either to the first output port 111 or to the second output port 112. The switch 2b can likewise allocate the frequency range ch3 either to the first output port 111 or to the second output port 112, independently of the allocation of the frequency range ch2.
In the examples shown in FIGS. 14-15, a specific signal filter 120 can be connected to a single input port and a single output port at the same time while still providing the possibility to change the connection configuration. This results in a large number of necessary signal filters depending on the desired compositions of the output signals.
Thus, there is a need for a building block allowing for an increased operational flexibility of switchable electronic circuits. Further, there is a need for a building block allowing for a decreased complexity of switchable electronic circuits.